Scroller Certifications

Fallback Behavior

Unsupported platforms will display the fully functional creative as an inline banner with the height of the placement dynamically adjusted to the current height of the viewport.

Trafficking & Placement Requirements

The following requirements must be met for the Interscroller format to function correctly.

Placement

• The tag must be placed either inline, directly in the page's HTML, or served through an IAB-friendly iframe.

• Hostile, SafeFrame and non-IAB Friendly iFrame wrapping are not supported.

• If the tag is served inside any other iframe type, the Interscroller is limited to the iframe area and cannot behave as a full-width Interscroller.

Viewport and Scrolling

• The page must include a mobile-optimized viewport tag, for example:

<meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no"/>

• The format assumes that the window containing the page is scrollable. To verify this, type window.scrollBy(0, 100) into the browser's JavaScript console. If the page scrolls down, the page is scrollable. If nothing happens, the page or a parent container may be preventing scrolling.

Parent Container Requirements

• Similar to other Celtra formats, the parent container must have a defined width (set value or 100%) if the placement container does not have a set width. Learn more about how universal trafficking works.

• The tag must not be nested in containers that make their own content scrollable, such as elements with overflow: scroll or overflow: auto where the content exceeds their explicit size.

• Ancestor elements of the placement must not use CSS float properties.

• The tag should only be nested inside elements that use the default height behavior or height: auto.

• Ancestor elements of the placement should not use CSS properties that create a new containing block (such as transform), as these can interfere with Interscroller positioning.

If these properties cannot be removed from a parent container, contact Celtra Support. In some cases, Celtra can apply a runtime workaround to preserve the expected Interscroller behavior.

Placement & Publisher Recommendations

Follow these recommendations to ensure optimal Interscroller performance.

• Place the trafficking tag inline and below the fold so users naturally scroll to the placement.

• We recommend using a 300 × 250 or 1 × 1 placement, as these are common inventory sizes for Interscroller delivery. However, other placement sizes are also supported.

When certifying new publishing partners for custom format (Interscroller or Miniscroller) for programmatic delivery, please follow the steps below:

• Exchange partner or Celtra Support provides the publisher with test tags or provides steps for generating tags.

• Publishing partner will provide a test page where the tags have been trafficked.

• Celtra Support will ‘spot check’ the test page directly on a mobile device to confirm expected rendering & behaviour.

• Exchange partner will provide Celtra Support with a test page for final rendering verification.

• If the ad unit renders and functions as expected, the domain is then certified for delivery.

If there are problems or inconsistencies with how the unit renders or behaves, verify the following:

• Is the unit being served to a SafeFrame, Hostile iFrame or non-friendly iFrame?

• Does the page include the required mobile viewport tag?

• Is the page scrollable?

• Are any ancestor elements using CSS float properties or CSS properties such as transform?

• Are there fixed headers and footers that are obstructing the unit?

• Is the inventory positioned below the fold?

If none of these issues appears, but there are still problems with the rendering of the unit, the partner should forward the issue to Celtra Support for further review.

Start the certification process by completing the form here.